Apparatus for producing filter rods or the like

ABSTRACT

A filter rod making apparatus wherein a web of wrapping material is draped around a compacted rod-shaped filler of fibrous material to form a tubular wrapper. The marginal portions of the web are bonded to each other by a layer of heat-activatable or heat-hardenable adhesive which is caused to set during travel of the wrapper through a passage of circular cross-sectional outline. A portion of the surface which surrounds the passage is provided on an elongated rib of a heating or cooling device which influences the adhesive and exerts a pressure against the seam which is formed by the overlapping marginal portions of the web.

United States Patent i [1 1 Block et a1.

APPARATUS FOR PRODUCING FILTER RODS OR THE LIKE Inventors: Hans-Jurgen Block; Heinz Greve;

Horst Zessin, all of Hamburg, Germany Hauni-Werke Korber & Co. KG, Hamburg, Germany Filed: May 17, 1972 Appl. No.: 253,925

Related US. Application Data Continuation-impart of Ser. No. 181,996, Sept. 20, 1971, which is a continuation-in-part of Ser. No. 861,829, Sept. 29, 1969, abandoned.

Assignee:

Foreign Application Priority Data 156/498, 499, 203,178; 93/1 C, 77 FT 1 Oct. 29, 1974 [56] References Cited UNITED STATES PATENTS 2,900,988 8/1959 Crawford et a1 131/267 3,060,814 10/1962 Wagner et a1. 93/1 3,619,328 11/1971 Preston et al 156/461 Primary Examiner-Daniel J. Fritsch Attorney, Agent, or FirmMichael S. Striker 5 7] ABSTRACT A filter rod making apparatus wherein a web of wrapping material is draped around a compacted rodshaped filler of fibrous material to form a tubular wrapper. The marginal portions of the web are bonded to each other by a layer of heat-activatable or heathardenable adhesive which is caused to set during travel of the wrapper through a passage of circular cross-sectional outline. A portion of the surface which surrounds the passage is provided on an elongated rib of a heating or cooling device which influences the adhesive and exerts a pressure against the seam which is formed by the overlapping marginal portions of the web.

PAIENKBW 29 19m 3. SHEH 20? 2 844 199 CROSSREFERENCE TO RELATED APPLICATION This is a continuation-in-part of our copending application Ser. No. 181,996 filed Sept. 20, 1971 for Method and apparatus for forming filter rods or the like," which in turn is a continuation-in-part application of Ser. No. 861,829, filed Sept. 29, 1969, now abandoned.

BACKGROUND OF THE INVENTION The present invention relates to apparatus for the making of rods wherein a tubular envelope of paper or other suitable wrapping material surrounds a rod-like filler of tobacco, fibrous filter material or the like. More particularly, the invention relates to improvements in apparatus for the making of rods which can be subdivided to yield cigarettes, cigars, cigarillos or filter rod sections.

Cigarettes, filter rod sections and like rod-like articles are normally produced in so-called continuous rod making machines wherein a continuous rod-like filler is confined in a tubular envelope or wrapper. The wrapper is draped around the filler so that its marginal portions overlap and are bonded to each other by a suitable adhesive. The adhesive can be applied to one or both marginal portions of the web which is converted into the wrapper prior to or during draping of the web around the rod-like filler. Such adhesive may be of the heat-activatable type (i.e., an adhesive which must be heated in order to become active and to bond two overlapping portions of a web or strip to each other) or a heat-hardenable adhesive which sets more rapidly if it is subjected to a heating action. If the adhesive is of the heat-activatable type, it may be heated prior to or during placing of the marginal portions of a wrapper into actual contact with each other. As a rule, the heatactivatable adhesive is thereupon cooled so as to insure that it furnishes a satisfactory bond between the two marginal portions. Such cooling can be effected in a tubular guide unit of the apparatus wherein the freshly formed increments of the rod advance toward a suitable cutoff.

It was found that the outline of a wrapped tobacco rod or a filter rod normally deviates from a desired outline, i.e., that the rod is often out of round. This can adversely influence further treatment of the sections which are obtained upon subdivision of the rod. For example, a wrapped tobacco rod section of circular cylindrical outline cannot be properly connected with an oval or substantially oval filter stud because the uniting band which connects one end of the tobacco rod section with one end of the stub is likely to provide at least one path for the inflow of atmospheric air during smoking of the filter cigarette. l

It was further found that, when a wrapped tobacco rod or a filterrod is being produced at a very high speed of up to 300 meters per minute, the time which is allowed for the setting of adhesive is so short that the seam of the tubular wrapper is likely to burst open, especially if the wrapper surrounds a rod-like filler of strongly compacted or condensed tobacco shreds or fibrous filter material. As a rule, the seam of the wrapper on the rod is scanned by a suitable detector which automatically arrests the apparatus in response to detection of a defective seam. This causes substantial losses in output.

SUMMARY OF THE INVENTION An object of the invention is to provide a novel and improved apparatus which is capable of insuring that the cross-sectional outline of a rod wherein a tubular wrapper surrounds a filler of tobacco or other fibrous material does not deviate, or does not appreciably deviate, from a desired or optimum outline even if the rod is produced at a very high rate of speed.

Another object of the invention is to provide a compact, relatively simple and reliable apparatus which insures rapid setting of adhesive in the seam of a tubular wrapper which surrounds a rod-like filler of compacted elastic fibrous material.

A further object of the invention is to provide an apparatus which is particularly suited for the making of filter rods and wherein proper setting of adhesive is insured irrespective of the exact nature of adhesive which is utilized in the seam.

An additional object of the invention is to provide an apparatus which can be rapidly converted for the making of rods from different types of wrapping material and/or different types of adhesive.

Our invention resides in the provision of an apparatus for producing a rod wherein a rod-like filler of fibrous or like material is confined in a web having overlapping marginal portions which are bonded to each other by at least one layer of heat-activatable or heathardenable adhesive. The apparatus comprises a bobbin, a roll or an analogous source of preferably convoluted web (e.g., a strip of paper or reconstituted tobacco), an endless belt or analogous conveyor means for transporting the web lengthwise from the source along a predetermined path, means for feeding a continuous rod-like filler (e.g., tobacco shreds or acetate fibers) into a first portion of the path, and converting means for draping successive increments of the web around successive increments of the filler in a second portion of the path so that the marginal portions of the thus draped web overlap and contact each other whereby the web is converted into a tubular wrapper having a longitudinally extending seam which is formed by the two marginal portions and the layer of adhesive between such marginal portions. The converting means comprises guide means which defines a passage bounded by a surface which influences the outline of the tubular wrapper. In accordance with a feature of the invention, the guide ,means includes adhesiveinfluencing means which is adjacent to the seam of the tubular wrapper in the passage Su ch adhesiveinfluencing means preferably includes a (heating and/ or cooling) device for influencing the temperature of adhesive and for preferably applying a predetermined pressure to the exterior of the seam in the passage of the guide means.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved rod forming apparatus itself, however, both as to its construction and its mode BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary perspective view of a rod forming apparatus which embodies one form of the invention;

FIG. 2 is a fragmentary side elevational view of a portion of a second rod forming apparatus; and

FIG. 3 is a transverse vertical sectional view as seen in the direction of arrows from the line Ill-III of FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. I, there is shown a portion of an apparatus which is utilized for the production of a continuous filter rod 28. The apparatus is of the type known as KDF and produced by Hauni-Werke, Korber and Co., KG, of Hamburg-Bergedorf, Western Germany. The illustrated portion of the rod forming apparatus comprises a converting assembly 1 which serves to convert a web or strip 14 of paper or the like into a tubular wrapper which forms part of the rod 28 and surrounds a condensed or compacted filler of fibrous material (e.g., acetate fibers). The converting assembly 1 comprises a web folding or draping unit 2 and a rod guide unit 3 which is located immediately downstream of the unit 2, as considered in the direction of lengthwise transport of the web 14 and rod 28 (arrow D).

The means for feeding a rod-like filler into the path for the web 14 immediately upstream of the folding or side of the filler whereby the web 14 is converted into a tube wherein the other marginal portion (which carries the adhesive layer 17) extends tangentially from a tubular portion which surrounds and confines the tiller. The cover plate 26 recedes or terminates in a third zone C wherein the adhesive-coated marginal portion of the web 14 is folded down by a second folder plate 27 which thus completes the conversion of the web 14 into a tubular wrapper or envelope wherein the overlapping marginal portions contact each other and are bonded to each other by the adhesive layer 17. The two marginal portions then form with the adhesive layer 17 a longitudinally extending seam 62 which faces upwardly, as viewed in FIG. 1.

The thus obtained rod 28 is then caused to enter an elongated passage 40 defined by a top or cover plate 3a and base plate 3b of the guide unit 3. The passage 40 is bounded by a cylindrical surface which determines the outline and the diameter of the tubular wrapper of the filter rod 28. The width W of the web 14 and the a diameter of the passage 40 are selected in such a way draping unit 2 includes a conventional horn 4 which receives a loose tow 6 of fibrous filter material from a treating station (not shown) and converts such tow into a rod-like filler which thereupon advances with and at the speed of the web 14. The latter is supplied by a supply reel or bobbin l4 and is transported lengthwise by an endless conveyor belt 7 which is trained over a small roll 9 located below the horn 4, a larger roll or drum 8 which is located at the discharge end of the guide unit 3, and a set of three tensioning rolls ll, 12 and 13. At least one of these rolls is driven to move the upper stretch of the belt 7 in a direction to the left, as viewed in FIG. 1. The treatment of the material of the tow 6 can be carried out in a manner and in an apparatus as disclosed in U.S. Pat. No. 2,900,988 to Crawford.

The convoluted web which forms the roll 16 is provided at one of its sides with three longitudinally extending narrow layers or films l7, l8, 19 of heatactivatable adhesive. The layer 17 is immediately or closely adjacent to one marginal portion of the web 14 and the layers I8, 19 are spaced from each other and may be located substantially midway between the layer 17 and the other marginal portion of the web. A heatactivatable adhesive which can be utilized in the apparatus of FIG. I is being produced by the West German Firm BOSTIK GmbH, of Oberursel/Taunus, and is sold under the Catalogue No. l 194.

The means for activating the adhesive of the layers 17, 18 and 19 upstream of the folding or draping .unit 2 comprises a heater device 21 which is shown as being located immediately upstream of the horn 4. This heater device comprises an elongated infrared heater 23, a source 22 of electrical energy for the heater 23, and a paraboloid reflector 24 behind the heater.

The exact details of the folding or draping unit 2 form no part of the present invention. It comprises means for deforming the belt 7 and the web 14 thereon so that that the seam 62 of a properly formed tubular wrapper of the rod 28 has a predetermined width. The top plate 30 of the guide unit 3 defines the upper half of the surface which surrounds the passage 40, and that portion of this upper surface half which contacts the seam 62 can influence the adhesive between the overlapping marginal portions of the seam 62 by withdrawing heat from such adhesive to insure rapid setting whereby the tubular wrapper is strong enough to withstand the tendency of the confined filler to expand as soon as successive increments of the rod 28 leave the guide unit 3. The rod 28 is then transported through a conventional cutoff (not shown) which serves to subdivide the rod into sections or stubs of desired length. Such stubs are ready for transport to a machine for the making of filter cigarettes, cigars or cigarillos, or to storage.

The top plate 30 of the guide unit 3 is preferably movable relative to thebase plate 3b so as to afford access to the surfaces surrounding the passage 40 for periodic inspection and/or cleaning. For example, the plate 3a can be pivotally secured to the base plate 3b by means of a hinge having a pintle which is indicated at 41 and extends in parallelism with the passage 40. Thus, the plate 3a can be pivoted in and counter to the direction indicated by the arrow E.

The main purpose of the guide unit 3 is to hold the tubular wrapper and the filler of the rod 28 againstradial expansion during travel through the passage 40 so that each increment of the rod which issues at the discharge end of the passage 40 has a predetermined diameter. Moreover, that portion of the concave surface of the top plate 3a which contacts and exerts a pressure against the seam 62 influences the heat-activatable adhesive of the layer 17 to promote its bonding action and to withdraw at least some heat so that the adhesive sets not later than when it advances beyond the plates 3a and 3b.

The operation of the apparatus which includes the structure of FIG. 1 is as follows:

sembly l. The heater 23 heats the layers l7, l8 and 19 of heat-activatable adhesive at the upper side of the web 14 so that such adhesive is in an optimum condition to furnish a satisfactory bonding action. The underside of the horn 4 has a cutout through which the condensed rod-like filler passes on its way into the path for the web 14.

The draping of the web 14 around the filler takes place in the zones A, B and C in a manner as described above, and the thus obtained filter rod 28 then enters the passage 40 between the plates 3a and 3b of the guide unit 3. The adhesive layer 17 bonds the overlapping marginal portions of the tubular wrapper and the seam 62 is pressed by the concave surface of the plate 3a so that its curvature corresponds to that of the remaining portion of the tubular wrapper. The layers 18 and 19 bond the wrapper to the adjacent fibers of the rod-like filler. Even though the filler has a tendency to expand and to open the seam 62, the treatment of the adhesive layer 17 in the passage 40 normally suffices to insure that the diameter of the wrapper does not change when the rod leaves the guide unit 3 and advances (arrow D) toward the aforementioned cutoff.

FIGS. 2 and 3 illustrate a portion of a second rod forming apparatus with modified adhesive-influencing means 61. Such adhesive-influencing means 61 comprises a cooling device which cools the seam 62 of the tubular wrapper which forms part of the filter rod 28. The cooling device can be said to form part of the guide unit in the apparatus of FIGS. 2 and 3 and comprises an elongated projection or rib 64 having a surface'63 which contacts the seam 62 and whose width, as considered in the circumferential direction of the rod 28, preferably equals or closely approximates the width of the seam. This insures that the cooling device influences only the layer 17 of heat-activatable adhesive which bonds the overlapping marginal portions of the tubular wrapper to each other. The projection 64 is provided at the outer side of an elongated heat exchanger pipe 66 which forms part of the cooling device and is surrounded by a block 67 of heat-insulating material. The block 67 is mounted in and can be said to form part of the cover plate 103a of the guide unit 103. This cover plate 103a is pivotally connected to the base plate 103b by a hinge 70 so that the projection 64 can be lifted off the seam 62 in the passage 140 of the guide unit 103. Furthermore, the block 67 is preferably adjustable in and counter to the direction indicated by the arrow F so that it can move the surface 63 on the projection 64 relative to the plate 103a toward or away from the axis of the rod 28 in the passage 140. The rib 64 and preferably the entire heat exchanger pipe 66 preferably consists of a metallic material (such as copper) having good heat conducting characteristics.

As shown in H0. 2, the ends of the pipe 66 are connected with a supply conduit 68 and an evacuating conduit 69 so as'to allow for circulation of a suitable coolant, e.g., tap water which withdraws heat from the projection 64 so that the latter can withdraw heat from the adhesive layer 17 in the seam 62. lnstead of water, one can employ another coolant, e.g., an organic fluid such tional as FRIGEN (trademark). If the coolant is an organic fluid, the cooling device of the adhesive-influencing means 61 preferably includes a heat exchanger wherein the fluid is cooled after it leaves the conduit 69 and prior to reentering the conduit 68.

The concave surface of the base plate 10312 of the guide unit 103 is provided with a trough-shaped recess to receive the belt 7 which transports the filter rod 28 through the passage 140 toward the cutoff. The edge portions of the belt 7 may extend into the cover plate 103a to insure that the belt 7 surrounds a substantial part of the external surface of the tubular wrapper in the passage 140. FIG. 3 shows that the pressure which is applied by the surface 63 of the projection 64 may result in slight flattening of the rod 28 in the region of the seam 62. Such deformation disappears due to innate elasticity of the confined rod-like filler as soon as the rod 28 emerges from the channel 140. For example, the extent of deformation of the rod 28 by the projection 64 may be in the range of 2 millimeters; this insures the generation of satisfactory pressure which suffices to guarantee that the overlapping marginal portions which form the seam 62 will adhere to each other after they leave the passage 140. It was found that the just described extent of deformation is amply sufficient to insure that, when the seam 62 emerges from the guide unit 103, it assumes an arcuate shape which corresponds to that of the remaining portion of the tubular wrapper so that the wrapper of the rod 28 which leaves the guide unit 103 is a substantially circular cylinder. The application of substantial mechanical pressure to the external surface of the seam 62 also promotes the setting of heat-activatable adhesive which forms the layer 17.

1f the adhesive which forms the layer 17 is a convenheat-hardenable adhesive, the influencing means 61 preferably constitutes a heating device which is provided with a pump or the like to circulate a stream of a heated fluid (e.g., oil) whereby such fluid enters by way of the conduit 68 and leaves by way of the conduit 69 to heat the pipe 67 and the filler to expand.

When the apparatus is at a standstill, the block 67 is moved in the direction indicated by the arrow F and/or the cover plate 103a is pivoted in the direction indicated by the arrow E so as to prevent a burning or charring of the rod 28in the passage 140. The apparatus may comprise a suitable device, e.g., an electromagnet or a hydraulic or pneumatic cylinder, which automatically pivots the plate 103a to an open position in re sponse to stoppage of the belt 7. The adjustability of the block 67 with reference to the cover plate 103a (in and counter to the direction indicated by the arrow F) is intended to allow for accurate adjustments in the position of the surface 63 relative to the axis of the rod 28 in the passage and to thus compensate for different thicknesses of wrapping material which forms the web 14. Furthermore, the position of the projection 64 with reference to the axis of the rod 28 might necessitate some adjustment if a first type of heat-activatable or heat-hardenable adhesive (layer 17) is replaced with a adhesivedifferent type of adhesive which might require the application of a more or less pronounced pressure against the exposed side of the seam 62.

The pressure which the projection 64 must apply against the seam 62 is normally a function of the speed at which the web 14 is being conveyed through the passage 140, Le, the pressure must be increased by moving the projection 64 inwardly if the speed of the belt 7 increases.

An important advantage of the improved apparatus is that it insures satisfactory setting of adhesive in the seam 62 regardless of whether the adhesive is of the heatactivatable or heat-hardenable type. Moreover, the adjustability of the projection 64 and/or cover plate 3a or 103a renders it possible to select an optimum pressure for different types of wrapping material and/or different types of adhesive. Also, the slight deformation of rod 28 in the passage 140 insures that the tubular wrapper of the rod assumes a circular cylindrical outline after it emerges from the guide unit 103.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range or equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. Apparatus for producing a rod wherein a rod-like filler of fibrous or analogous material is confined in a web having overlapping marginal portions which are bonded to each other by at least one layer of adhesive, comprising a source of web; conveyor means for transporting'the web lengthwise from said source along a predetermined path; means for feeding'a continuous rod-like elastic filler into a first portion of said path; and converting means for draping successive increments of the web around successive increments of the adhesive-influencing means further includes a device filler in a second portion of said path so that the marginal portions of the thus draped web overlap and contact each other whereby the web is converted into a substantially cylindrical wrapper having a longitudinally extending seam and surrounding the filler in compacted condition of the filler, said converting means comprising guide means defining a passage for said tubular wrapper and including adhesive-influencing means engaging the seam of the wrapper in said passage, said guide means having a first surface bounding the major part of said passage and said adhesiveinfluencing means comprising a projection extending inwardly beyond said first surface and having a seamengaging second surface of a width which is substantially equal to the width of the seam, said second surface being in contact with said wrapper only in the region of the seam and having a configuration to temporarily flatten the seam.

2. Apparatus as defined in claim 1, further comprising means for moving said projection with reference to said first surface.

3. Apparatus as defined in claim 1., wherein said projection is movable substantially radially of said passage to thereby regulate the pressure which is applied to said seam.

4. Apparatus as defined in claim 1, wherein said adhesive-influencing means comprises a cooling device.

5. Apparatus as defined in claim 1, wherein said guide means comprises a plurality of separable portions and said projection is provided in one of said separable portions. v

6. Apparatus as defined in claim 1, wherein said adhesive-influencing means further comprises a heating device.

7. Apparatus as defined in claim 1, wherein said for changing the temperature of adhesive.

8. Apparatus as defined in claim 7, wherein said device includes a heat exchanger. 

1. Apparatus for producing a rod wherein a rod-like filler of fibrous or analogous material is confined in a web having overlapping marginal portions which are bonded to each other by at least one layer of adhesive, comprising a source of web; conveyor means for transporting the web lengthwise from said source along a predetermiNed path; means for feeding a continuous rod-like elastic filler into a first portion of said path; and converting means for draping successive increments of the web around successive increments of the filler in a second portion of said path so that the marginal portions of the thus draped web overlap and contact each other whereby the web is converted into a substantially cylindrical wrapper having a longitudinally extending seam and surrounding the filler in compacted condition of the filler, said converting means comprising guide means defining a passage for said tubular wrapper and including adhesive-influencing means engaging the seam of the wrapper in said passage, said guide means having a first surface bounding the major part of said passage and said adhesive-influencing means comprising a projection extending inwardly beyond said first surface and having a seam-engaging second surface of a width which is substantially equal to the width of the seam, said second surface being in contact with said wrapper only in the region of the seam and having a configuration to temporarily flatten the seam.
 2. Apparatus as defined in claim 1, further comprising means for moving said projection with reference to said first surface.
 3. Apparatus as defined in claim 1, wherein said projection is movable substantially radially of said passage to thereby regulate the pressure which is applied to said seam.
 4. Apparatus as defined in claim 1, wherein said adhesive-influencing means comprises a cooling device.
 5. Apparatus as defined in claim 1, wherein said guide means comprises a plurality of separable portions and said projection is provided in one of said separable portions.
 6. Apparatus as defined in claim 1, wherein said adhesive-influencing means further comprises a heating device.
 7. Apparatus as defined in claim 1, wherein said adhesive-influencing means further includes a device for changing the temperature of adhesive.
 8. Apparatus as defined in claim 7, wherein said device includes a heat exchanger. 